VIENNA (Reuters) -- The UN nuclear watchdog has said it is in "stalemate" with Iran on key issues of trust but says that Israeli and French suggestions it is hiding evidence of alleged Iranian atom bomb work is baseless.

Comments by IAEA chief Mohamed el-Baradei could be timely for Western powers who will strive in coming weeks to win over Russia and China to far harsher sanctions against Iran.

An August 28 International Atomic Energy Agency (IAEA) report said Iran had granted an IAEA demand for tighter monitoring of its Natanz nuclear fuel-production site and restored some IAEA access to a heavy-water reactor site of proliferation concern.

But it also said Iran had increased its number of installed centrifuge machines by 1,000 to 8,300, boosting potential enrichment capacity, and was still blocking an IAEA inquiry into allegations it has tried to "weaponize" the enrichment process.

Except for Iran's two new gestures of cooperation, "On all...issues relevant to Iran's nuclear program, there is stalemate," el-Baradei said in remarks opening a quarterly meeting of the IAEA's 35-nation Board of Governors.

He referred to the blocked weaponization inquiry, Iran's refusal to suspend enrichment as demanded by the UN Security Council, and its failure to adopt an IAEA protocol permitting inspections ranging beyond declared nuclear sites.

The West suspects Iran is pursuing the means to produce atomic bombs behind the facade of a civilian nuclear program. Iran says it wants only electricity from uranium enrichment.

President Mahmud Ahmadinejad declared the same day that Iran will continue uranium enrichment.

Compelling, Though Unproven

The IAEA report described as compelling Western intelligence material implying Tehran secretly combined uranium processing, airborne high-explosive tests and efforts to revamp a missile cone in a way that would fit a nuclear warhead.

It said Iran must clarify the matter instead of just rejecting the intelligence as fabricated.

"I am dismayed by the allegations of some member states, which have been fed to the media, that information has been withheld from the [IAEA] board. These allegations are politically motivated and totally baseless," he said.

"Such attempts to influence the work of the [IAEA's nonproliferation inspectorate] and undermine its independence and objectivity are in violation of...the IAEA Statute and should therefore cease forthwith."

But he underlined the gravity of the intelligence material and said Iran must grant access.

Iran has repeatedly declared the entire matter "closed.".

French Foreign Minister Bernard Kouchner said last week the IAEA had yet to publish annexes of findings on Iran which he said were important for an assessment of possible military dimensions to Iran's enrichment campaign.

Israel's Foreign Ministry said the IAEA report did not reflect all the agency knows about Iran's "efforts to continue to pursue its military [nuclear] program."

The Jewish state is Iran's arch-foe believed to harbor the Middle East's only nuclear arsenal. Israel has been lobbying six world powers to intensify efforts to stop Iran's nuclear activity -- by crippling sanctions or even last-resort war.

A senior diplomat close to the IAEA told Reuters the agency had collected further information on alleged military aspects to Iran's nuclear program but this had not yet been properly checked for veracity, and so has not been released.